In the Linux kernel, the following vulnerability has been resolved:
mm: swap: fix race between free_swap_and_cache() and swapoff()
There was previously a theoretical window where swapoff() could run and
teardown a swap_info_struct while a call to free_swap_and_cache() was
running in another thread. This could cause, amongst other bad
possibilities, swap_page_trans_huge_swapped() (called by
free_swap_and_cache()) to access the freed memory for swap_map.
This is a theoretical problem and I haven't been able to provoke it from a
test case. But there has been agreement based on code review that this is
possible (see link below).
Fix it by using get_swap_device()/put_swap_device(), which will stall
swapoff(). There was an extra check in _swap_info_get() to confirm that
the swap entry was not free. This isn't present in get_swap_device()
because it doesn't make sense in general due to the race between getting
the reference and swapoff. So I've added an equivalent check directly in
free_swap_and_cache().
Details of how to provoke one possible issue (thanks to David Hildenbrand
for deriving this):
--8<-----
__swap_entry_free() might be the last user and result in
"count == SWAP_HAS_CACHE".
swapoff->try_to_unuse() will stop as soon as soon as si->inuse_pages==0.
So the question is: could someone reclaim the folio and turn
si->inuse_pages==0, before we completed swap_page_trans_huge_swapped().
Imagine the following: 2 MiB folio in the swapcache. Only 2 subpages are
still references by swap entries.
Process 1 still references subpage 0 via swap entry.
Process 2 still references subpage 1 via swap entry.
Process 1 quits. Calls free_swap_and_cache().
-> count == SWAP_HAS_CACHE
[then, preempted in the hypervisor etc.]
Process 2 quits. Calls free_swap_and_cache().
-> count == SWAP_HAS_CACHE
Process 2 goes ahead, passes swap_page_trans_huge_swapped(), and calls
__try_to_reclaim_swap().
__try_to_reclaim_swap()->folio_free_swap()->delete_from_swap_cache()->
put_swap_folio()->free_swap_slot()->swapcache_free_entries()->
swap_entry_free()->swap_range_free()->
...
WRITE_ONCE(si->inuse_pages, si->inuse_pages - nr_entries);
What stops swapoff to succeed after process 2 reclaimed the swap cache
but before process1 finished its call to swap_page_trans_huge_swapped()?
--8<-----
In the Linux kernel, the following vulnerability has been resolved:
clk: qcom: mmcc-apq8084: fix terminating of frequency table arrays
The frequency table arrays are supposed to be terminated with an
empty element. Add such entry to the end of the arrays where it
is missing in order to avoid possible out-of-bound access when
the table is traversed by functions like qcom_find_freq() or
qcom_find_freq_floor().
Only compile tested.
In the Linux kernel, the following vulnerability has been resolved:
wireguard: netlink: access device through ctx instead of peer
The previous commit fixed a bug that led to a NULL peer->device being
dereferenced. It's actually easier and faster performance-wise to
instead get the device from ctx->wg. This semantically makes more sense
too, since ctx->wg->peer_allowedips.seq is compared with
ctx->allowedips_seq, basing them both in ctx. This also acts as a
defence in depth provision against freed peers.
In PHP version 8.1.* before 8.1.28, 8.2.* before 8.2.18, 8.3.* before 8.3.5, if a password stored with password_hash() starts with a null byte (\x00), testing a blank string as the password via password_verify() will incorrectly return true.
In the Linux kernel, the following vulnerability has been resolved:
firmware: arm_scmi: Harden accesses to the reset domains
Accessing reset domains descriptors by the index upon the SCMI drivers
requests through the SCMI reset operations interface can potentially
lead to out-of-bound violations if the SCMI driver misbehave.
Add an internal consistency check before any such domains descriptors
accesses.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_set_pipapo: do not free live element
Pablo reports a crash with large batches of elements with a
back-to-back add/remove pattern. Quoting Pablo:
add_elem("00000000") timeout 100 ms
...
add_elem("0000000X") timeout 100 ms
del_elem("0000000X") <---------------- delete one that was just added
...
add_elem("00005000") timeout 100 ms
1) nft_pipapo_remove() removes element 0000000X
Then, KASAN shows a splat.
Looking at the remove function there is a chance that we will drop a
rule that maps to a non-deactivated element.
Removal happens in two steps, first we do a lookup for key k and return the
to-be-removed element and mark it as inactive in the next generation.
Then, in a second step, the element gets removed from the set/map.
The _remove function does not work correctly if we have more than one
element that share the same key.
This can happen if we insert an element into a set when the set already
holds an element with same key, but the element mapping to the existing
key has timed out or is not active in the next generation.
In such case its possible that removal will unmap the wrong element.
If this happens, we will leak the non-deactivated element, it becomes
unreachable.
The element that got deactivated (and will be freed later) will
remain reachable in the set data structure, this can result in
a crash when such an element is retrieved during lookup (stale
pointer).
Add a check that the fully matching key does in fact map to the element
that we have marked as inactive in the deactivation step.
If not, we need to continue searching.
Add a bug/warn trap at the end of the function as well, the remove
function must not ever be called with an invisible/unreachable/non-existent
element.
v2: avoid uneeded temporary variable (Stefano)
An incorrect type conversion vulnerability exists in the DVPSSoftcopyVOI_PList::createFromImage functionality of OFFIS DCMTK 3.6.8. A specially crafted malformed file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.
In the Linux kernel, the following vulnerability has been resolved:
scsi: Revert "scsi: fcoe: Fix potential deadlock on &fip->ctlr_lock"
This reverts commit 1a1975551943f681772720f639ff42fbaa746212.
This commit causes interrupts to be lost for FCoE devices, since it changed
sping locks from "bh" to "irqsave".
Instead, a work queue should be used, and will be addressed in a separate
commit.